OE
Answer choice A states that the United States had been providing military and economic aid to the Allied Powers before the attack on Pearl Harbor. This statement indicates that the United States was not entirely neutral before the attack and had already been supporting the Allied Powers. If the United States was already providing aid to the Allied Powers, it suggests that the Japanese attack on Pearl Harbor may not have been the only factor that caused the United States to enter World War II. Instead, it suggests that the United States may have entered the war sooner or later regardless of the Japanese attack on Pearl Harbor. Therefore, answer choice A weakens the conclusion that the Japanese attack on Pearl Harbor was the sole reason for the United States entering World War II.
Answer: A